Probably because a lot of stuff in this series appears to be derivative of modern photos or artwork. See the modified ai_arctic_warfare (which wouldn't work; there's no room for the bolt to move) in post #1676027 and the thinly-disguised AR-15/M203 and visibly-translucent overlaid calf sheath in post #1676028. In this post, you can see an Aimpoint (and the distinctive giant thumbscrew of the QRP/QRP2 mounts), chopped-up AN/PEQ-2 LAM/illuminator unit, and M320 leaf sight.
Edit: Tone, which came off rather more negative than I intended. It's an interesting series/concept, I'm just saying the real-world kit (however futurized) probably comes from the base work in most of these.